Regenerate build scripts
    
    Vanilla icecast-2.4.4 build fails on EPEL6:
    
    aclocal.m4:17: warning: this file was generated for autoconf 2.69.
    You have another version of autoconf.  It may work, but is not guaranteed to.
    If you have problems, you may need to regenerate the build system entirely.
    To do so, use the procedure documented by the package, typically 'autoreconf'.
    configure.in:7: error: Autoconf version 2.65 or higher is required
    aclocal.m4:427: AM_INIT_AUTOMAKE is expanded from...
    configure.in:7: the top level
    autom4te: /usr/bin/m4 failed with exit status: 63
    
    Because the build scripts require newer autoconf. To fix it, this commit
    regenerate the autotools-generated scripts.